How to Calculate Your Macros for Muscle Gain (Without Overthinking It)
You can train well and still stall if your nutrition isn't pointed at the goal. For building muscle, that means a modest calorie surplus and enough protein to support new tissue. You can set your numbers in about five minutes.
Step 1: Find maintenance calories
Maintenance is the intake that keeps your weight stable. The fastest estimate is a TDEE formula based on your stats and activity. Start with our TDEE calculator. Treat the output as a starting hypothesis: your real maintenance is whatever holds your weight steady over two weeks.
Step 2: Add a lean-gain surplus
You need surplus energy to gain muscle, but past a point more surplus mostly adds fat. A surplus of roughly 10% over maintenance (about 250–300 kcal for most people) is enough. Off-season guidance for bodybuilders puts the useful range at about 10–20% [2].
The big-surplus tax
A large surplus adds weight fast, but much of it is fat you'll have to diet off later, and the longer cut that follows costs you training quality. A slower gain is usually leaner over a year.
Step 3: Set protein first
Protein is the macro with the strongest evidence for muscle gain [1]. Aim for 1.6–2.2 grams per kilogram of bodyweight (about 0.7–1.0 g per pound). In the largest meta-analysis, the benefit leveled off around 1.6 g/kg, with 2.2 g/kg as the upper end of the estimate [1]. Total daily intake matters far more than timing.
For an 80 kg lifter, that's roughly 130–175 g of protein per day. MuscleBuddy sets protein at the top of that range, 2.2 g/kg, to leave a margin.
Step 4: Fat floor, then carbs fill the gap
Keep dietary fat at 20% of calories or more (for most lifters that is about 0.6–0.8 g/kg), since very low-fat diets are linked to lower testosterone. Give the remaining calories to carbohydrate, your main training fuel. More carbs tend to support harder sessions, which is what you want while gaining.
Tip
The macro calculator sets protein, fat, and carbs from your goal and bodyweight in one step. It starts fat at 75 g, capped at 35% of calories. Its bulk preset adds 500 kcal, the top of the usual range; for a leaner gain, choose maintain and add your own ~10%.
Step 5: Adjust based on real data
Your starting numbers are an estimate. Let the scale correct them:
- Gaining faster than ~0.5% of bodyweight a week (about 2% a month): trim carbs by ~10%.
- Not gaining at all over 3–4 weeks: add ~150 kcal of carbs.
- Strength climbing, waist stable: leave it alone.
Let the app do the watching
MuscleBuddy tracks your rolling weigh-in average and flags when your gain is running faster or slower than your goal's band, so you adjust from the trend rather than a single weigh-in.
The short version
Estimate maintenance, add ~10%, set protein at 1.6–2.2 g/kg, keep fat at 20% of calories or more (about 0.6–0.8 g/kg for most lifters), fill the rest with carbs, and recheck against the scale every few weeks.
Get your protein, carb, and fat targets in one click.
Informational only, not medical advice. Consult a qualified clinician before changing medication, hormones, or supplements.
Garrett Wilson
Founder, MuscleBuddy
Garrett Wilson is the founder of MuscleBuddy, a longtime lifter and bodybuilder, and the engineer who built its training, nutrition, health and upkeep modules. He started MuscleBuddy out of his own spreadsheets, training seriously while managing health complications and autoimmune conditions with no product that would hold both halves at once. Where a guide here gives a health or training number, it cites the study the number comes from.
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